During these frigid winter days, there are many people who dream about trips to far-off tropical resorts. A fortunate few will actually escape the ice and snow to bask in the sunshine. The rest of us can only dream, snapped back to our New Year's reality by a mailbox chock full of tax return packets and bills representing our contribution to the December retail sales index.

January is a lean and frugal month, a time to resolve to eat less, exercise more, and save money for that trip to warmer climes. I find that I am best fortified to pursue this spartan routine by pizza, an inexpensive food that is festive and just slightly decadent. The accompanying salad helps justify the calories. An order of garlic bread, oozing with butter, often unclogs any stuffed nasal passages with Mother Nature's odorous antidote to the common cold.A ride home with a few steaming pizzas fogging the windows in my car and saturating the goose down in my parka with the various smells of a freshly baked crust, herbs, tomato sauce, melted cheese, mingled with the plethora of toppings one can now choose from, is almost as exciting as a trip on the Love Boat. Add a few Danny Kaye movies for the VCR and you have sure cure for the winter blues.

I had a certain sense of this pleasant anticipation while driving home with a hot order of several pizzas from San Francisco Sourdough Pizza, a relatively new independent pizzaria on Main Street downtown. The interior is clean and uncluttered, reflecting an efficient and focused approach to the task at hand - pizza. Except for a lengthy list of self-serve beverages, a salad (94 cents), soft ice cream (47 cents), and some cinnamon rolls and brownies, the menu is strictly pizza.

Prices are moderate, ranging between $8 and $10 for whole pizzas. Pizza by the slice costs $1.24 for the cheese and tops out at $1.88 for either a slice of the combination or the seafood and crab. San Francisco Sourdough also offers "take n' bake" pizzas that are about $1.50 cheaper than those prepared on the premises. Other toppings include pepperoni, Canadian bacon and pineapple, a combination of veggies and other toppings and a special of the day.

We sampled several of the toppings, including the linguica, a spicy sausage, the seafood combination, mainly ersatz crab chunks and a white pizza, topped only with cheese and a sprinkling of herbs. The latter does not compare to the white pizzas I have had back East, which are actually a thicker layer of ricotta cheese and garlic and other herbs on top of the crust. But the different melted cheeses blended nicely with the seafood and the thick chewy crust made for a filling and appetizing meal.

The tomato sauce is ample, chunky and nicely seasoned. The other toppings are also generously applied and fresh. The dominant texture is provided by the freshly baked crust, which has just a hint of the sweetness one expects in freshly baked bread. The sourdough flavor was very mild; I had wanted a bit more punch.

The individual salads were a crisp blend of lettuces, as well as bits of red cabbage, croutons, fresh mushrooms and pepperoni. The homemade sweet poppy seed dressing was a pleasant treat; other choices include Italian, bleu cheese and Ranch.

San Francisco Sourdough Pizza offers downtown pizza lovers and those bound for home with the responsibilities for dinner an attractive and appealing choice. The menu pays attention to key ingredients of freshness and taste and offers a probable remedy for any winter gloom.

Rating: *** 1/2

San Francisco Sourdough Pizza, 159 S. Main, 364-9333. Open from 8 a.m. to 6 p.m., Monday through Friday. Free delivery in the downtown area. Accepts checks with guarentee card.